A power plug with over temperature and over current protection is disclosed in CN patent No. 200720196044.1 which is issued as CN201163690 on Dec. 10, 2008 to the assignee of the present application and incorporated herein in its entirety by reference. Referring to FIGS. 1 and 2, the power plug comprises a housing 1, terminals 2, 3 and 4 partially embedded in the housing 1, and power cables 5, 6 and 7. The terminal 2 is a live terminal. An over temperature and over current protection unit 100 is provided inside the housing 1 and connected in series between the terminal 2 and the power cable 5 of the power plug. Referring to FIG. 2 which shows an interior structure of the power plug, the protection unit 100 has a bimetallic strip 40 located at a side close to a metal shell 20, and a thermistor 50. An electrical connection end, on which a wiring card 24 is disposed, extends from the metal shell 20 and is electrically connected to the live terminal 2 through a conductive wire 80, which is in turn received and held by a second wiring card 70. The power plug can provide protection against over temperature and over current conditions.
However, the live terminal 2 of the power plug mentioned above is connected to the electrical connection end of the protection unit 100 through a conductive wire. Due to the presence of other materials, such as plastic of the power plug, the conductive wire and the wiring card, between the live terminal and the protection unit, heat can not be directly transferred from the live terminal to the protection unit, thus heat transfer efficiency and response speed of the protection unit are reduced.